MODERN BIOLOGY 34I 



he has laid the foundations upon which subsequent research has built 

 further. 



His controversy with Geoffroy Saint-Hilaire 

 In the writings which Cuvier produced during the last years of his life there 

 stands out with increasing distinctness his clear, though narrow, concep- 

 tion of the interrelation of animal types. This is especially conspicuous in 

 his controversy with Geoffroy Saint-Hilaire, which attracted much atten- 

 tion in his own time and has been keenly debated by later generations, up 

 to the present day. These two had indeed been friends from youth and had 

 for a long time loyally collaborated. Gradually, however, their ways parted. 

 Cuvier insisted more and more upon the truth of his principles regarding 

 the immutability of species and the incomparability of types, while Geoffroy 

 became more and more deeply engrossed in the study of the comparison of 

 organs in different animal forms and speculations inferred therefrom upon 

 the question of one uniform type of life. Cuvier did not like personal con- 

 troversy; his objections to views of which he did not approve he invariably 

 made without personal remarks and clothed in a sometimes rather haughty, 

 but always courteous, style. While, then, Geoffroy for years propounded 

 his fantastic comparisons between the segments of the Articulata and the 

 vertebra;, tortoise-shell, and mussel-shell, which have been referred to in 

 the foregoing, Cuvier never directly opposed these, to him, absurd ideas, 

 but, on the other hand, formulated with increasing distinctness his own 

 theories and his arguments against all that contradicted them. At last, how- 

 ever, came the inevitable clash, in the year 1830. Geoffroy had submitted 

 to the Academy of Science a paper written by two younger scientists, con- 

 taining a detailed comparison between ink-fish and vertebrates: the ink-fish 

 was regarded as a vertebrate animal reflexed in the middle, with the anal 

 opening pressed on to the head, possessing a diaphragm, cartilages corre- 

 sponding to the cranial bones, and in general most of the organs peculiar 

 to a vertebrate animal. The essay contained a direct attack on Cuvier, 

 though this passage was struck out when sent to the press; but it was read 

 before the Academy, and therefore called for a reply. This produced from 

 Cuvier a courteous but sharp criticism dealing with the whole of Geoffroy's 

 natural-scientific speculation; by illustrating side by side the organs of an 

 ink-fish and of a vertebrate animal in the reflexed position, which it had been 

 claimed constituted the likeness between them, he demonstrated the funda- 

 mental difference between the organs common to both, both in structural 

 detail and position, showing, moreover, that many organs existing in the 

 one form do not occur at all in the other. But, besides this, Cuvier rejected 

 the entire fundamental principle on which Geoffroy based his research, at the 

 same time emphasizing the latter's brilliant services as an exponent of 

 the comparative anatomy of vertebrates. He made special reference to the 



